Broccoli Casserole from Scratch
2 ½ lbs. broccoli florets, cut into bite-size pieces (about 8 cups)
6 tbsp. butter, divided
1 cup finely chopped button mushrooms
¼ cup flour
1 cup whole milk
½ cup half-n-half
½ tsp. salt
¼ tsp. freshly ground black pepper
½ cup Greek yogurt
1 cup finely chopped yellow onion
1 ½ cups grated cheddar cheese
1 ¼ cups whole-wheat breadcrumbs
Preheat oven to 350 degrees.
"Bring a large pot of water to a boil. Add broccoli and boil for 4 minutes. Transfer to a colander, rinse with cold water, and drain. Place broccoli in a large bowl."
"Meanwhile, melt 1 tablespoon of the butter in a medium saucepan over medium-low heat. Add the mushrooms and cook until soft, about 4 minutes, stirring occasionally. Transfer mushrooms to the bowl with the broccoli."
"In the same saucepan, melt 4 tablespoons of the butter over medium heat. Whisk in the flour until smooth; cook, whisking constantly, 30 seconds. Whisk in the milk and half-n-half. Bring to a low simmer and continue to whisk constantly until thickened. Remove from the heat and stir in the salt, pepper, and Greek yogurt."
"Pour sauce into the bowl with the broccoli and mushrooms. Add the onion, egg, 1 cup of the cheddar cheese, and ½ cup of the breadcrumbs. Stir to combine. Transfer to the prepared baking dish."
"Melt the remaining tablespoon of butter and stir into the remaining ¾ cup breadcrumbs. Stir in the remaining ½ cup cheddar. Sprinkle breadcrumb topping over the casserole.
Bake for 45 minutes, until filling is hot and bubbly. Check after 30 minutes and cover with foil if topping is browning too quickly. Let stand 10 minutes before serving."